FAILURE TO CLOSE VALVE AT LAKE ILSANJO LEAVES OFFICIALS HOPING FOR RAIN

Scott Amarant and his son Cory, 10, and dog Sushi, of Santa Rosa usually fish in the reeds at Lake Ilsanjo in Annandel State Park, but now fish from the exposed mud flats after officials released a large amount of water from a valve at the dam.

photo by John Burgess/The Press Democrat

March 29, 2008, 6:37AM

03/29/2008

Lake Ilsanjo, a reservoir in the hills above Santa Rosa at Annadel State Park, needs rain after park officials allowed the water level there to drop well below normal this winter.

"The valve apparently was not closed early enough and so inadvertently it drained down a little bit farther than was anticipated," said Mary Pass, a parks official.

The water level has dropped all the way down to the release valve at the base of the dam. State officials said Friday that they were unsure if the lake had ever been this low before.

Now, without an unusual amount of spring rainfall, the lake likely will dry up this summer or autumn, said Mike Drake, a Rohnert Park resident who has fished Ilsanjo for 10 years.

"There go the fish," Drake lamented.

Parks officials said they need to better monitor the operation of the release valve that was installed at the lake's earthen dam five years ago.

With the ability to release water through the valve, parks officials try to reduce flows over the spillway while still holding back enough water to keep the lake at a level for fishermen and the sightseers to enjoy in spring and summer.

"We do the best we can to balance" those priorities, said parks ecologist Marla Hastings.

"We were expecting more rain," Pass said. "We still think that there will be additional rain that will assist in filling that a little bit more than it is right now."

The reservoir was built on Spring Creek in the 1950s, before the land became a popular state park on the edge of Sonoma County's largest city.

In earlier years, the lake had no real spillway, only a gully where the water poured down when the lake level rose significantly during winter storms.

In 2003, the state spent nearly $400,000 to build a spillway to the gully and to add the release valve at the dam in an attempt to reduce erosion in the gully.

On Friday afternoon, as the gray skies started to sprinkle, the lake level drew mixed reactions from hikers and fishermen visiting Annadel.

Martha Barton of Santa Rosa said she and a friend had asked the parks staff this winter whether they were releasing too much water.

She acknowledged it would be hard to anticipate whether March would be wet or dry. But to the suggestion that spring rains might refill the reservoir, she replied, "Good luck."

Fisherman Scott Amarant of Santa Rosa, casting at the lake with his 10-year-old son, Cory, and friend Ian Montgomery, said the fishing wasn't as good now "because you can't fish the tules."

The tules are sitting out of the water.

Amarant was philosophical about the lower water level. But he did acknowledge the past pleasure of jumping into the lake after cycling there on a warm summer day: "Oh definitely, after coming up that hill."

Parks official John Crossman disputed the suggestion that fish are at risk.

Since the valve was installed, the lake level in winter has fallen significantly only to recover later in the spring, Crossman said. Nonetheless, he said, "We need to pay more attention" in regard to the effect of the releases on the lake level.

Drake, the fisherman, said there is little that parks officials can do now but hope for rain. But if the fish and other aquatic creatures in the lake eventually die, he wants the parks department to put Ilsanjo "back the way it was" once the winter rain storms return.

Lake Ilsanjo, a reservoir in the hills above Santa Rosa at Annadel State Park, needs rain after park officials allowed the water level there to drop well below normal this winter.

"The valve apparently was not closed early enough and so inadvertently it drained down a little bit farther than was anticipated," said Mary Pass, a parks official.

The water level has dropped all the way down to the release valve at the base of the dam. State officials said Friday that they were unsure if the lake had ever been this low before.

Now, without an unusual amount of spring rainfall, the lake likely will dry up this summer or autumn, said Mike Drake, a Rohnert Park resident who has fished Ilsanjo for 10 years.

"There go the fish," Drake lamented.

Parks officials said they need to better monitor the operation of the release valve that was installed at the lake's earthen dam five years ago.

With the ability to release water through the valve, parks officials try to reduce flows over the spillway while still holding back enough water to keep the lake at a level for fishermen and the sightseers to enjoy in spring and summer.

"We do the best we can to balance" those priorities, said parks ecologist Marla Hastings.

"We were expecting more rain," Pass said. "We still think that there will be additional rain that will assist in filling that a little bit more than it is right now."

The reservoir was built on Spring Creek in the 1950s, before the land became a popular state park on the edge of Sonoma County's largest city.

In earlier years, the lake had no real spillway, only a gully where the water poured down when the lake level rose significantly during winter storms.

In 2003, the state spent nearly $400,000 to build a spillway to the gully and to add the release valve at the dam in an attempt to reduce erosion in the gully.

On Friday afternoon, as the gray skies started to sprinkle, the lake level drew mixed reactions from hikers and fishermen visiting Annadel.

Martha Barton of Santa Rosa said she and a friend had asked the parks staff this winter whether they were releasing too much water.

She acknowledged it would be hard to anticipate whether March would be wet or dry. But to the suggestion that spring rains might refill the reservoir, she replied, "Good luck."

Fisherman Scott Amarant of Santa Rosa, casting at the lake with his 10-year-old son, Cory, and friend Ian Montgomery, said the fishing wasn't as good now "because you can't fish the tules."

The tules are sitting out of the water.

Amarant was philosophical about the lower water level. But he did acknowledge the past pleasure of jumping into the lake after cycling there on a warm summer day: "Oh definitely, after coming up that hill."

Parks official John Crossman disputed the suggestion that fish are at risk.

"There's still a fair amount of water there," he said.

Since the valve was installed, the lake level in winter has fallen significantly only to recover later in the spring, Crossman said. Nonetheless, he said, "We need to pay more attention" in regard to the effect of the releases on the lake level.

Drake, the fisherman, said there is little that parks officials can do now but hope for rain. But if the fish and other aquatic creatures in the lake eventually die, he wants the parks department to put Ilsanjo "back the way it was" once the winter rain storms return.